Textile product of synthetic organic filaments having randomly varying twist along each filament



June 1, 1965 A. 1.. BREEN ETAL l t e e h m 4 I m V e A e H S WW nTEXTILE PRODUCT OF SYNTHETIC ORGANIC FILA RANDOMLY VARYING TWIST ALONGEACH F Filed June 6, 1965 ALVIN L BREEN HERBERI G. LAUTERBACH ATTORNEYJune 1, 1965 A'.| BREEN ETAL 3,135,155

TEXTILE PRODUCT OF SYNTHETIC ORGANIC FILAMENTS HAVING RANDOMLY VARYINGTWIST ALONG EACH FILAMENT 4 Sheets-Sheet 2 Filed June 6, 1965 oal g aTENACITY, 6P0

INVENTORS ALVIN L. BREEN HERBERT G. LAUTERBACH ATTORNEY June 1, 1965Filed June 6, 1963 FILLING INDEX OI b N WORK T0 COHPRESS I0 psi, (INCHLBS.)

A. L. B EE TEXTILE PRODUCT OF S R N ETAL RANDOM YNTHETIC ORGANICFILAMENTS HAVING LY VARYING TWIST ALONG EACH FILAMENT 4 Sheets-Sheet 3Ely-10 FILAHENT BREAK ELONGATION, /o

El'g,.11

INVENTORS ALVIN L. BREEN HERBERT G. LAUTERBACH BY nmd 2 cazm y ATTORNEYJ1me 1965 A. BREEN ETAL 3,186,155

TEXTILE PRODUCT OF SYNTHETIC ORGANIC FILAMENTS HAVING RANDOMLY VARYINGTWIST ALONG EACH FILAMENT Flled June 6, 1963 4 Sheets-Sheet 4 F I G. I 3

no. DIRECTION or 0F TURNS TVIST jfqavsnsu POINT ,e -REVERSAL POINT/-REVERSAL POINT s eXkREVERS/fl PQINT REVERSAL POINT INVENTORS ALVINLEONARD BREEN HERBERT GEORGE LAUTERBACH BY Q BW ATTORNEY United StatesPatent TEXTELE PRGDUCT 6F SYNTHETEC ORGANIC FILAMENTS HAVING RANDOMLYVARYING TWEST ALQNG EACH FELAMENT Alvin Leonard Breen and Herbert GeorgeLanterhach,

Wilmington, Del., assignors to E. I. du Pont de Nemours and Company,Wilmington, Del, a corporation of Delaware Filed June 6, 1963, Ser. No.287,464 27 Claims. (Cl. 57140) This application is acontinuation-in-part of our copending applications Serial No. 698,103,filed November 22, 1957, and Serial No. 842,524, filed September 25,1959, now abandoned, the latter being a continuation-inpart of ourapplication Serial No. 772,475, filed November 7, 1958 and abandoned.

This invention relates to a process for treating a bundle of filamentssuch as yarn or thread to produce a multifilament yarn of greatlyincreased tenacity and dyeability. More particularly, the inventionrelates to a bulky yarn composed of a plurality of individually crimpedfilaments having a random, three-dimensional, curvilinear configuration,high tenacity and improved level dyeing characteristics and fasterdyeing rate and to the process used for preparing such yarn.

Artificial fibers are normally produced most easily as continuousfilaments. These continuous filament yarns are very strong because ofthe absence of loose ends that are unable to transmit imposed stresses.Their extreme uniformity and lack of discontinuity, however, makeconventional continuous filaments yarns much more dense than yarns madefrom staple fibers. The production of yarn from staple fibers, however,is time-consuming and requires a complex series of operations to crimpthe fibers, align the fibers into an elongated bundle and then to drawthe bundle to successively smaller diameters. The final spinningoperation, which involves a high degree of twist, finally binds thesediscontinuous fibers together to produce a coherent yarn withconsiderably increased bulk. The occluded air spaces give them alightness, covering power, and warmth-giving bulk not normally possiblewith continuous filament yarns. Thus to get staple fibers that can beprocessed on conventional wool or cotton spinning equipment, it has beenthe practice to cut continuous filament yarns such as rayon, acetate,nylon, as well as the polyacrylic and polyester fibers into shortlengths for spinning into staple yarn.

Recent developments in the textile industry have provided useful routesfor improving the bulk and covering power and recoverable elongation ofcontinuous filament yarns without resorting to the staple spinningsystems of the prior art. A well-known process for making stretch yarninvolves the steps of twisting, heat-setting and then backtwisting to alow final twist level. Anotheryarn of improved bulk is preparedcommercially by the steps of twisting, heat-setting and backtwistingon-the-run using a false-twisting apparatus. This end product can befurther modified by hot relaxing to improve the bulk and handle. Stillanother bulk yarn is being prepared by the well-known stuifer boxtechnique wherein the yarn is steamed to heat-set while it is in acompressed state in the stutter box.

All of these yarns of the prior art are produced by a process which hasthe common elements of deforming the yarn mechanically and thenheat-setting either with or without an after relaxation step. It was notuntil the recently disclosed product in US. 2,783,609 to Breen and itsprocess of manufacture became known that an entirely new techniquebecame available for improving the bulk of continuous filament yarns.This technique involves exposing a filamentary material to a rapidlymoving turbulent fluid, thereby inducing a multitude of crunodalfilament loops at random intervals along the individual filaments. Theseloops and snarls of entangled loops increase the bulk of thecontinuous-filament yarns considerably and result in fabrics of improvedcover, bulk, handle, and the like. With the invention of Breen, a newtool is available for the bulking of filamentary structures, i.e., aturbulent fluid. Fluids, of course, have been used for yarn treating inmany of the prior art operations such as drying, extracting,transporting, and the like. Until the invention of Breen, however, theyhad not been used to entangle, convolute, and bulk a filamentarymaterial. It has now been discovered, however, that a new processutilizing the turbulent fluid technique results in new yarn productsthat have certain unique properties not heretofore disclosed in the art.

It is an object of the present invention, therefore, to providecontinous filaments and continuous-filament yarn having a bulkinessgreater than staple yarn spun from comparable fibers. Another object isto provide multifilament yarn resembling spun staple in its desirablelightness, covering effectiveness and warmth-giving bulk but retainingthe characteristic continuous filament freedom from loose ends,fuzziness, and pilling. It is also an object to prepare a bulkyfilamentary material especially useful for the pile component of pilefabrics. It is another object to provide both crimped and uncrimpedsynthetic organic filamentary strands having high tenacity and anunusually high rate of dyeability. Other objects will appearhereinbelow.

According to this invention there are provided synthetic organicfilamentary strands having a combination of high tenacity and a rate ofdyeability which has not been attained heretofore. These products areproduced by feeding a synthetic organic filamentary strand at anoverfeed of at least about 12% to a plasticizing stream of acompressible fluidi in which the individual filaments, while in aplastic state, are momentarily separated from each other and thencooled. The strand may be cooled by passing through air at normal roomtemperature. The product has high tenacity and also possesses a rate ofdyeability at least about greater than that of the feed strand. Byincreasing the overfeed to at least 30%,

preferably at least 40%, the filamentary product produced contains, inaddition to the high tenacity and high rate of dyeability set forthabove, fibers possessing an independent random persistent,three-dimensional, nonhelical, curvilinear configuration along the lineof the filamentary strand and is substantially free of stable crunodalloops.

The invention and the manner of carrying it out will be more clearlyunderstood by reference to the drawings in which,

FTGURE 1 is a schematic perspective view of apparatus suitable for theproduction of the bulky yarn of this invention,

FIGURE 2 shows a jet device useful in the production of the yarn of thisinvention,

FIGURE 3 is a cross-sectional View of the bulky yarn of this invention,

FIGURE 4 is a longitudinal view of single filaments modified inaccordance with the process of this invention,

FIGURE 5 is a longitudinal view of a multi-filament yarn of thisinvention,

FIGURES 6 and 7 show variations of the multi-filament yarn product ofthis invention,

FIGURE 8 shows a single filament produced in accordance with thisinvention from a fiber of non-round cross section,

FIGURE 9 shows a graphical relationship between the dye absorption andorientation angle of the product of this invention, and its tenacity,

FIGURE 10 shows a graphical relationship of the pilla ing index of theproduct of this invention, and its break elongation,

FIGURE 11 shows a graphical relationship of compressionalcharacteristics versus weight for pile carpets made of the yarn of thisinvention compared with conventional staple yarn,

FIGURE 12 is an illustration of a fiber cross section for preparation ofa preferred carpet yarn, and

FIGURES 13 and 14 are schematic representations of the structuralcharacteristics of the filaments of this invention.

In FIGURE 1, the moving threadline 31 to be treated is passed throughguide 32, between feed rolls 33 and 34, over guide 35, through fluid jet36, over guide 37, through quench tube 38, provided with cooling fluidthrough opening 39, through guide 20, to guide 43, or alternatelybetween feed rolls 41 and 42. Traverse guide 44 may be used todistribute the bulky yarn on package 46 driven by roll 45 or part 46 maybe a roll which with roll 45 is used to feed yarn to piddle tube 47provided with aspirating tube 48 depositing yarn in container 49.

FIGURE 2 is a similar jet consisting of body member 115, yarn guide 116,and orifice I17. Compressible fluid enters the body member throughopening 118, and the yarn enters through opening 119.

FIGURE 3 is a thin cross section of the yarn showing short lengths offilaments in randomly disposed arrangement. Fibers at points a show arandom wrapping effect which in some cases improves the cohesiveness ofthe yarn bundle without inhibiting its bulkiness and stretch properties.The freedom from protruding loops indicated here gives desirableimprovement in yarn handling characteristics and freedom from snaggingproblems in end use form. The yarn cross section was made by supportingthe sample in a transparent mounting of polymethyl methaerylate prior tosectioning so as to hold the short len ths of fibers in position.

FIGURE 4 is an illustration of the individual filaments of theinvention. Points show what appear to be angular crimp form. This isintended to represent a region where the filament path is in the generaldirection perpendicular to the plane of the illustration causingapparent distortion of the curvilinear form.

The above statements apply similarly to the filaments comprising theyarns illustrated in FIGURES 5, 6, and 7.

FIGURE 5 shows a multifilament yarn composed of filaments of FIGURE 4and it can be seen that the filaments are substantially interentangledwithin the yarn bundle. FIGURE 6 shows a yarn bundle such as in FIGURE 5after having been false twisted. FIGURE 7 also shows a yarn bundlecomposed of filaments of FIG- URE 4 and containing a divided regioncharacterized by opposite directions of twist in the adjacent portionsthereof.

FIGURE 8 depicts a single filament of this invention having a non-roundcross section.

FIGURE 9 expresses graphically the relationship between orientationangle, tenacity, and dye absorption rate to illustrate the data ofExample XI.

FIGURE 10 shows graphically the relationship be tween pilling index andfilament break elongation as explained more fully in Example 1.

FIGURE 11 shows graphically the work required to compress carpets ofvarious weights prepared from staple yarns as described more fully inExample V.

FIGURE 12 shows a cross section of a trilobal filament in which x is theaxis of the filament, which is defined for present purposes as a linerunning lengthwise through the cross-sectional center of gravity of thefilament, and e is a point on the surface of the filament. D representsthe smallest circle circumscribing the filament, and d is the largestcircle which can be inscribed within the filament. The ratio of theradii of D to d is called the modification ratio of the filament.

FIGURE 13 depicts a tensioned filament c of this invention having anon-round cross section with e representing a single element on thesurface of the filament (a line on the surface of the filament which, inthe straight filament, prior' to twisting or crimping of the filament,is straight and parallel to the axis of the filament), also shown bypoint e in the cross-sectional view of FIGURE 12. It will be noted inFIGURE 13 that the direction of twist is alternately S and Z in adjacentsections of the filament. The angle of twist of the filarnent at anypoint h of element 1: is shown by angle a, the acute angle between atangent t to element e at that point and plane i (perpendicular to theplane of the paper) which contains both the axis of the filament andpoint It. In filaments of this invention, both crimped and uncrirnped,twist angle or varies continuously and randomly throughout the length ofthe filaments.

FIGURE 14 is a schematic view of a crimped filament 0 of this inventionas viewed under a pair of Nicols prisms crossed at Because of the crimp,only portions 7 of the filament lie at an angle of 45 to the planes ofpolarization of the prisms and also perpendicular to the line of viewthrough the prisms. In the birefringence pattern exhibited by filamentsof this invention the lines of constant retardation g lie parallel tothe axis of the filament throughout the filament length, although theyhave maximum visibility only in those portions of the filament. Byproper manipulation of the filament it can be seen that the lines ofretardation are parallel to the axis of the filament throughout thefilament length, thereby distinguishing prior art crimped filamentswherein the lines of retardation are parallel to the filament axis onlyin straight portions of the filament. This method is especially usefulfor identifying round filaments of this invention because the twistedconfiguration as shown in FIGURE 13 may be very difficult to observe ina round filament even under high magnification.

For certain uses where subdued luster and tactile dryness are desiredthe preferred product of this invention should be made from fibershaving a non-round shape of critically selected character. In carpetyarns, for example,

'it has been found that the approximately symmetrical cross-sectionalform indicated in FIGURE 12 is preferred. This is disclosed by Hollandin US. Patent No. 2,939,201 issued June 7, 1960.

The individual filaments of the products of this invention arecharacterized by possessing alternate S and Z twist sections throughouttheir lengths, with at least one S turn and at least one Z turn per inchof filament which have a twist angle averaging at least 5. This twist isfurther characterized by random variation along the filament length,having a random number of turns between twist reversals, having a randomcontinuously varying angle of twist along its length, and having arandom number of twist reversals per inch. Nevertheless, the filamentsare free from cross-sectional deformation, as contrasted to the deformedcross-sections characteristic of gear-crimped filaments and thoseproduced by mechanical bulking processes in general.

These important properties of filaments of this invention areparticularly noticeable with non-round fiber forms as illustrated inFIGURE 8. Here the fiber has not only a random, three-dimensional,non-helical, curvilinear configuration, but is also formed into arandomly twisted configuration, portions of which are in an S directionwith other portions being in a Z direction. The twist is completelyrandom along the length of the filament particularly with respect to (1)the angle of twist which varies continuously and randomly, (2) thenumber of twist recounted).

To determine the extent of the random twist modification of theindividual fiber, a specimen is mounted between microscope slides withsufficient tension to hold the fiber axis in an approximately straightcondition but a tension low enough that the twist is not appreciablyreduced. The angle is then measured between imaginary lines followingthe outermost points of the filaments and the filament axis at a numberof points sufi'icient to provide a meaningful aver-age. This averageangle should be at .east 1. There will he points where the angle isessentially zero where the twist reverses direction. Other points arefound Where the angle is considerably greater than the average value. Inwell modified samples maximum values in the order of 30 are observed andthe average may be as much as 5 or more.

Since the twist of each filament is random along its length, a yarn madeup of a group of these non-round filaments is prevented from packing ina closely nested configuration. This is true even when considerabletension is applied to the yarn sufiicient to straighten the randomcurvilinear crimp configuration. This latter property is particularlyuseful in increasing the bulk of tightly woven fabrics where loomtension and fabric construction tends to reduce the bulking effect dueto crimp. The random twist is likewise useful in highly crimped pileyarns or bulky knit structures Where it tends to reduce objectionableglitter or luster associated with light reflection from the fibersurfaces.

By a direct experiment, it has been possible to confirm the presence ofrandom alternating twist in round filaments treated by the process ofthis invention. A nylon yarn was prepared having round filaments withtwo polymeric components spun side-by-side. One half of each filamentcontained .02% TiO pigment and the other 2.0% pigment. The filaments,examined under the microscope, were initially free of twist as indicatedby the line of demarcation between the two filament halves. treatment asdescribed, the treated filaments were found to have a high degree ofrandom alternating twist, the angle of twist at many points along thefilament being equivalent to turns per inch.

In the preferred process of this invention, filaments and yarns meetingthe above objects are provided by a process in which a stream of acompressible fluid at a temperature above the second-order transitiontemperature of the polymer of which the filament is made and preferablyat least about 300 F. is vigorously jetted to form a turbulentplasticizing region. The yarn or filaments to be treated are positivelyfed at a rate greater than the yarn take-up speed into the fluidplasticizing stream so that the yarn is supported by it and individualfilaments are separated from each other and crimped individually bywhipping about in the hot turbulent plasticizin g region, and rapidlycooled while being maintained at low tension to set the convolutions.Under these conditions the yarn temperature is above the cold point asdescribed more fully hereinafter and below the melting point of theyarn. During the jetting treatment, filament shrinkage occurs because ofthe heat transmitted to the fibers. The process elements such astemperature, pressure, fluid flow, yarnspeed, tension, and wind-up speedare adjusted so as to give a final yarn denier (measured in relaxed formafter hot-wet relaxation) greater than the feed yarn denier andpreferably at least greater than the feed yarn denier.

The crimped filaments are withdrawn from the plasticizing zone by thefluid exhaust and the take-up rolls. The filaments pass through acooling zone before or after the take-up rolls to prevent further.plastic flow and to insure retention of the crimp while maintaining theyarn in a substantially relaxed and tensionless condition. Aftercooling, the yarn may be tensioned to remove any fiber loops, eliminateany packing of filaments and to improve the bulking characteristics ofthe yarn. Tensioning is desirable also for forming a suitable package onany wind-up device. Tension applied in pulling the yarn away from thejet or in winding the yarn on a package appears to cause some temporaryremoval of fiber crimp, but this crimp is After fluid subsequentlyrecovered when the yarn is relaxed and boiled-off. Stable crunodal loopsare avoided or at least kept to a minimumv by control of the processconditions since such entangled loops prevent maximum bulk from beingobtained in the yarns. The crimped yarn, of course, may be cut intostaple after passing through the turbulent hot fluid. This process,therefore, provides a highly productive way of crimping tow which is tobe used in staple products. This process may also be used for settingdyes in the yarn. A yarn padded with dyes may be either treated with aturbulent fluid to set the dyes in the fiber by diffusion through thefiber or it may be treated with a turbulent fluid to simultaneously bulkthe yarn and set the dyes.

Bulky yarn can be prepared by the process of this invention from anyplasticizable fiber. The process is applicable primarily to continuousfilament yarns and multifilament yarns in particular althoughmonofilaments can also be crimped in the same manner. Staple yarns canalso be processed to give products of greatly increased crimp and bulkparticularly in the surface fiber.

Bulky products of this invention are different in funda mental physicalstructure from any of the bulked yarns described in prior art. Duringthe jetting treatment, at least 12% lengthwise shrinkage of thefilaments and sub stantial deorientation of the filaments occur. Whenjetted under optimum conditions, this shrinkage and relaxation farexceeds that which occurs when the yarn is exposed to the same fluid atthe same temperature and under low tension for a long period of timewithout agitation. The instantaneous application of heat to fibers inthe jet and extremely short exposure time permit deorientation to occurbefore substantial crystallization can occur. The yarn does not,therefore, become permanently set before deorienting and does not becomebrittle or weak. This dynamic relaxation is responsible for aconsiderable amount of deorientation of the molecules and an increase incrystallinity. In addition, there is a significant increase in dyereceptivity with little loss in tenacity. The improved combination ofdyeability rate and tenacity of filaments of this invention can beexpressed by the equation where D and D are the dyeability rates of thefilament before and after shrinking, respectively, and T and T are thetenacities of the filament before and after shrinking, respectively.This relationship holds true for both crimped and uncrimped filaments ofthis invention.

The higher filament temperatures under relaxed condi tions and therepeated stressing cause the amorphous molecular structure to open-upgiving more lateral space between molecules and greater distance betweencrystallites along the fiber axis. The great changes in the amorphousmolecular structure are shown clearly by low angle X-ray patterns usingthe techniques described by W. O. Statton, J. Polymer Sci. 22, 385(1956). This new opened-up condition, plus the deorientation whichoccurs, gives fibers with greatly improved dyeing rate Withoutsubstantial reduction in tenacity. The dyeing rate is in creased about75% to 250% by the process of this invention and there is no change inthe chemical composition of the fiber during treatment. Of course,moderate improvements in dye rate have been shown in prior art byrelaxed heat treatment, but such increases in dye rate with such smalllosses in tenacity with luster advantages due to random twist have notbeen known. in addition, the uniform turbulent heating in the presentprocess permits much higher average filament temperatures to be obtainedsince there is no danger of surface filaments being heated above theirmelting point or fusing filaments.

All commercial procedures for manufacturing synthetic fibersinadvertently subject a portion of the yarn or certain segments of aportion of the yarn and filaments to plucks or other stresses as, forexample, when processing with fluids or passing over guides, whichcauses these yarns or segments to dye at a different rate and/ or to adifferent depth relative to the bulk of the yarn. Undesirabledeformations, which cause non-uniform dyeing, result from mechanicaltreatment of heat-softened filaments. This is particularly true ofprocesses in which hot filaments are mechanically twisted or pressedagainst surfaces or bent abruptly, as in mechanical twist-settingoperations and gear or stutter box crimping. The filament crosssectionsare deformed by pressure on the twisting device or other hard surface,by pressing together of cross filaments, and by sharp creasing of thefilaments. The dynamic relaxation employed in this invention avoidsthese non-uniformities in structure and produces filaments withexceptional dyeability and tenacity but without crosssectionalconfiguration distortions.

The yarns of this invention are uniform in cross section, .acharacteristic particularly noticeable with filaments of round orsymmetrical cross sections. The unusual uniformity of a filament of thisinvention may be seen by its uniform birefringence pattern under crossedNicols prisms as illustrated in FIGURE 14. By proper manipulation of theobserved filament, it will be seen that the lines of constantretardation in the pattern are parallel to the filament axis throughoutthe filament length as distinguished from prior art crimped filamentswhere such lines are parallel to the filament axis only in straightportions of the filament. The bulked yarns prepared by the process ofthis invention also have better dyeing uniformity than bulked yarnsprepared by the twist-heat set method, by gear crimping, by stutter-boxcrimping, or by other mechanical crimping methods which produce filamentdistortion during the crimping process.

The crimped products of this invention have a threedimensional,non-helical, random, curvilinear configuration. This structure isdifferent from the bulked materials prepared by the varioustwist-setting operations, since these have predominantly a helical andregular type of filamentary deformation. It is different also from thoseprepared by the Well-known stutter box technique, since the latter arecharacterized by the regular and reversing zig-zag planar type of crimpillustrated in Spence et al. U.S. Patent No. 2,917,784 dated December22, 1959. The crimp in the products of the present invention isthree-dimensional and random in crimp amplitude and period. Theturbulent fluid treatment of filaments which are free to crimpindividually results in a very high crimp level, and a curvilinear,random configuration, that is, the crimp in the filament is in the formof an irregular smooth curve throughout and entirely free from the sharpcreases and folds found in mechanically crimped filamentaryconfigurations. The filaments are substantially free from crunodalloops. The crimp is permanent to normal fiber processing conditions andwill persist in filaments taken from the yarn bundle. On exposure to hotWater, further increases in crimp amplitude and frequency are obtained.The useful products of this invention have a crimp level in excess ofper inch, preferably above per inch, and there may even be as high as 70or 80 crimps per inch.

The products of this invention can be prepared from any natural orsynthetic plasticizable filamentary material. A monocomponent syntheticorganic filament structure is preferred, i.e., each filament is formedfrom a single fiber-forming melt or solution; this includes mixtures ofmonocomponent filaments of different composition in multi-filamentstrands. Especially preferred are filaments composed of thermoplasticmaterials of the types illustrated herein. Exemplary thermoplasticmaterials include polyamides, e.g., poly (epsilon caproamide) andpoly(hexamethylene adipamide); cellulose esters, e.g., celluloseacetate; polyesters, particularly polyesters of terephthalic acid orisophthalic acid and a lower glycol, e.g., poly(ethylene terephthalate),poly(hexahydro-pxylylene terephthalate); polyalkylenes, e.g.,polyethylene, polypropylene, etc.; polyvinyls and polyacrylics, e.g.,polyacrylonitrile, as well as copolymers of acrylonitrile and othercopolymerizable monomers can be crimped to give the three-dimensional,random, curvilinear crimped configuration and the alternate and random Sand Z twist. Copolyrners of ethylene terephthalate containing less than15% combined monomers other than ethylene terephthalate andcopolymerizable with ethylene terephthalate are also very useful inpracticing this invention. While the preferred form of material iscontinuous filaments, the process and resultant improvements occur withstaple yarns as well. Both types of materials can be made into bulkyyarns and fabrics having improved bulk, covering power (opacity) andhand.

Products of this invention may be prepared from both monofilament andmultifilament yarns in textile deniers as well as the heavier carpet andindustrial yarn sizes either singly or combined in the form of a heavytow. Fine count and heavy count staple yarns can be processed bothsingles and plied. The process and product are also not restricted inthe case of the synthetic materials to any one particular type offilament cross section. Cruciform, Y-shaped, delta-shaped, ribbon, anddumbbell and other such filamentary cross sections can be processed atleast as well as round filaments and usually contribute still more bulkthan is obtained with round filaments.

The turbulent fluid used to treat the filamentary material may be air,steam, or any other compressible fluid or vapor capable of plasticizingaction on the yarn provided that it has a temperature above thesecond-order transition temperature of the filament. Hot air will givesufficient plasticization in the turbulent region for many fibersalthough it may be desirable for certain fibers to supplement thetemperature effect with an auxiliary plasticizing medium. Steam is acheap and convenient source of high pressure fluid with a compoundplasticizing action.

The temperature of the fluid medium must be regulated so that the yarntemperature does not reach the melting point of the fiber. However, withfibers made from fusible polymers, the most effective bulking and thegreatest productivity is obtained when the temperature of the turbulentfluid is above the melting point of the fiber. In this case the yarnspeeds should be great enough so that melting does not occur. Because ofthe great turbulence and the high heat, yarns are heated rapidly.Temperatures lower than the second-order transition temperature (T ofthe yarn material should usually not be employed because under theseconditions the crimping or bulking of the filaments is not permanent andutility of the fibers is reduced.

One of the essential elements of the process is that the filaments oryarn must be inherently elastic but must be rendered non-elastic andplastic in the turbulent atmosphere. The plastic condition may bebrought about by the temperature of the compressible fluid. In any case,the plastic condition of the filaments must be temporary and transitory.The term plasticizing or plastic is intended to mean that the conditionsto which the term relates are such that the filaments are in a temporaryflaccid, non-elastic, deformable condition. After the plasticizingconditions are removed such as by lowering the temperature, chilling,removing the solvent, or similar considerations, the filaments and yarnsmust return to their normal elastic state. The use of an inertcompressible fluid such as air or steam under conditions which do notplasticize, soften, or render the filaments nonelastic, does not fallwithin the scope of the invention. Wet steam will fail to produceconfigurations in the yarn described above if the temperature of theyarn does not reach a point sufficiently high to render it plastic andnon-elastic. Under such conditions, crimps and crunodal loops may beformed, but they are not stable and must be treated under plasticizingconditions to set and stabilize the crimps. On the other hand,relatively low temperatures may be used if there is sufficient residualvolatile solvent in the filaments. It wlil also be apparent that largeamounts of non-volatile plasticizers such as dibutyl phthalate,tricresyl phosphate, oils, plasticizing resins, etc., are relativelypermanent, and when these are present, the yarns will not return to anelastic condition and should be avoided except for special purposes.

At high speeds and with certain polymers the fiber temperature should bewell above the second-order transition temperature. A preferred minimumtemperature defined as a cold point is given by J. W. Ballou and I. C.Smith in the Journal of Applied Physics, Volume 20, page 499 (1949). Thecold point is the second inflection in the sonic modulus-temperaturecurve for the polymer or fiber in question. In general, this temperaturemay be 50 C. or more above the second-order transition temperature.

There are a number of means and apparatus whereby a turbulent stream offluid can be produced. Suitable jets or devices for treating afilamentary material with a turbulent plasticizing fluid to achieve theimprovements of this invention are described by Breen in US. Patents No.2,783,609 and No. 2,852,906, and by Hall in US. Patent No. 2,958,112.

The process is well adapted for using a number of ends of yarn in thesame jet. Thus, it is possible to pass two to five or more ends through:a single jet at the same time. The resulting yarn may have the endswell blended or it may have bulked ends which will be distinctly separate and independently windable depending on the processing conditions.Two or more yarns may also be treated using different tensions or feedrates so as to produce a tension stable bulky yarn with extensibilityconfined to that of the shorter member. Likewise, two different types ofyarn such as nylon and rayon may be passed through the jet. Thedifferential shrinkage and heat-setting of the two types of yarn providemany interesting effects which are desirable for aesthetic reasons intextile materials. The crimp of the product is extremely stable and isnot removed by subjecting the crimped fibers to tensions up to the drawtension; the crimp returns upon release of tension. The bulked yarnsdisclosed in US. Patent No. 2,783,609 require a high degree ofintertangling or twist in order to maintain their bulk properties. Thenew yarns described here are stable and keep their bulk even when thereis no entanglement or appreciable twist. Monofilament may be treated ina similar fashion to obtain a single crimped continuous filament. It isalso to be understood that any treatment of yarns herein disclosed is tobe construed as being applicable also to single filaments although forreasons of economy bundles of filaments or yarns are treated. The termyarn refers to any lon or continuous length of a bundle of filaments.

The process of this invention can produce a gross increase in the bulkof the filamentary structures. The comparison of the starting denier tothe final denier is a crude indication of the bulk increase. However, abetter measure of bulk can be obtained by determining the volume of adefinite weight of yarn while under pressure. This measurement of bulkunder compressional loads is useful for estimating the bulk which a yarnwill have when fabricated into carpet or other fabrics. It correlatesvery well, for example, with subjective compressions obtained by feelinga carpet with the fingers. For the purpose of this invention bulk is,therefore, measured under a pressure of 3.1 lbs/sq. in. The crimped yarnsamples are measured in the untwisted state, that is, with less than oneturn per inch in the gross yarn. Before testing, the untwisted yarn isgiven a hot wet relaxed treatment to develope maximum bulk and is thendried and conditioned at 70 F. and relative humidity. Weighed samples ofexactly 2.0 g. are then cut into /2 to inch pieces. The cut pieces arethen dropped at random into a hollow stainless steel cylinder having aninside diameter of 1.008 inches. A round stainless steel piston of1.000-inch diameter is then lowered slowly into the cylinder to compressthe yarn and finally to exert a pressure of 3.1 lbs./ sq. in. on the topof the yarn sample. After maintaining this pressure for seconds, thevolume of the compressed yarn is determined. The volume in cubiccentimeters divided by the weight of the yarn in grams is the specificvolume (cc./g.). This measurement is always made with a load of 3.1lbs./ sq. in. on the yarn. The specific volume of yarn prepared by thisprocess is much greater than the specific volume of yarns prepared byother crimping processes such as stuifer-box crimping, false swist-heatset, or knife-edge crimping. The specific volume of carpet yarnsprepared by this process ranges from 7 to 14 cc./ g. Carpet yarns fromother bulking processes, on the other hand, have specific volumes from 3to 7 cc./g.

The synthetic filamentary materials to be treated by the process of thisinvention should preferably be in a high state of orientation to reducepilling in the finished fabrics. Drawable filaments tend to snag andpull out of the fabrics. The resulting fuzz fibers then tend to wind-upinto fuzz balls usually referred to as pills in the finished fabric.When the oriented filamentary structures are passed under low tensionthrough the hot turbulent plasticizing fluid medium, a considerabledegree of deorientation and crystallization occurs.

Because of the unusually large increase in crystallinity, duringprocessing, the final yarns have a break elongation that is much smallerthan would be expected considering the large decrease in orientation.Similarly, the tenacity changes less than expected. At the same time,the yarns have a surprisingly high dyeing rate. The net result is toobtain unusual yarns having a desirable combination of .low elongation,low pilling tendency, and rapid dyeability. Filling is avoided becauseyarns of low elongation do not easily draw or pull out of the yarn orfabric when snagged to give long fuzz fibers. These undesirable fuzzfibers cause pilling by winding and entangling around one another untilballs of fuzz are formed. Of course, yarns with low elongations can beobtained in other bulk-yarn processes by drawing the feed yarnadequately, but these highly drawn yarns then have relatively low dyeingrates.

In addition to the increase in relaxed yarn denier due to the convolutedform, the high degree of deorientation that accompanies the relaxationin a preferred process results in a gross increase in the filamentdenier of the yarn being treated. Some increase in denier, of course,accompanies almost any relaxation or bulking process, i.e., 1-10%. Thefilament denier of the new products formed by the subject process,however, increases in denier from 12 to 25% or more as compared to thefilament denier prior to treatment. In this instance, of course, denieris measured by the change in filament weight per unit length with thecrimp removed by a light tension, eliminating the denier increaseassociated with crimp contraction.

The bulky yarns of the process of this invention are generallycharacterized by a very desirable tendency to develop increased crimpamplitude and yarn buikiness as a result of mechanical exercisingfollowed by the ap plication of heat and/ or plasticizer to the yarnwhile it is in a relaxed or low-tension condition. These steps coincidegenerally with the normal treatments involved in the formation of theusual fabric types and in the subsequent dyeing and finishingoperations. The tufting operation in the formation of a tufted carpet,for example applies momentary high tension to the pile yarn as thetufting needle forces the yarn through the backing fabric.

The loop, once in place, is in a low tension or relaxed state as thehot-wet finishing steps are used as, for example, in piece dyeing of thecarpet. The bulking action accompanying these treatments is particularlybeneficial in the tufted carpet since it causes the individual pileloops arse,

to increase their coverage of the backing material giving much improvedappearance. Increasing surface cover with the above treatments is notessential, however, because of the great bulking power inherent to theextensible random curvilinear filament form. On tensioning, for example,in the carpet tufting operation, the substantially continuous-filamentyarns of this invention are held in an essentially straight conditionwith a bulkiness little more than that of a conventional yarn of similarweight and filament count. Upon release of the tension as the tuftingneedle is withdrawn, however, the elastic recovery of the well-set crimpform causes the filaments to resume their randomly crimped configurationproducing a great increase in bulk of the individual tufts so that thebacking material is effectively obscured. Yarn portions held against thebacking fabric between adjacent tufts, however, remain in a low-bulktensioned condition. This gives a desirable preponderance of pile yarnon the face of the fabric and a minimum on the back. This appliessimilarly to other pile fabrics such as t1 so useful in upholstery.

In normal weaving and knitting operations, the bulking character of thisyarn is similarly beneficial. in sweater weight knit form, for example,the bulking action tends to obliterate undesirable threadiness. In wovenfabrics, this action gives improved covering power, a drier tactilequality, and increased fabric-to-fabric friction, as compared withfabrics of unmodified yarn.

Since tensioning and hot-wet finishing are important factors in theutilization of these bulky yarn products, tests were devised tocharacterize the response of the yarns to these treatments.

Yarn crimp elongation, abbreviated YCE, is a measure of theextensibility of the yarn of this invention. The method for measuringthis property employs a lightweight skein of yarn equivalent to about5000 denier (measured through the double loop thickness). With heavyyarns, a single loop will suffice for the test. The length is cut to anyvalue suitable for measurement of lengths in both the relaxed and tautcondition. A load of 0.5 gm./den. is applied to the sample. The load isthen reduced to 0.1 gm./den. At this latter load, the sample length ismeasured and recorded at L The Weight is removed and the sample istreated with atmospheriE steam until contraction ceases. The samplelength is remeasured and recorded as L Yarn crimp elongation, expressedas a percent change in crimped yarn length, is calculated as follows:

YCE is also a measure of crimp amplitude which in turn is a measure ofyarn bulkiness provided the crimp frequency is in a suitable range (5-50crimps/ inch) and random in character so that in-phase packing iseliminated. In general, for a desirable bulky yarn for the purposes ofthis invention a YCE of at least is necessary and 25% or more ispreferred.

Similar measurements may be applied to single filaments. In thisspecification the terms fiber and filament are used interchangeably.Filament or fiber crimp elongation, FCE, is determined by cutting aknown length of bulked yarn, separating the individual filaments fromthe yarn segment. The excess of length of the average filament whenextended sufficiently to remove the crimp divided by the length of theyarn segment and multiplied by 100, is the percent FCE. FCE may differfrom YCE because of such factors as interfibcr friction.

The bulked yarn denier, BYD, of the crimped yarn is measured in therelaxed state under the conditions described above for the measurementof L A tensioned yarn denier, TYD, may also be caiculated based on LDen;

17., Per cent shrinnage [r T X in which Den; is the denier of the yarnbefore treatment by this process and TYD is the tensioned yarn denier asdefined above. In order that the greatly improved dyeability may beachieved at acceptably low yarn elongation values, it is necessary thatthe true fiber shrinkage accompanying this process be at least 12% andpreferably 25% or more.

The fluid process used to produce the filaments of this invention notonly causes individual filaments to assume a randomly alternating twistand an irregular three-dimensional crimp configuration but also, when aplurality of filaments are processed simultaneously as a yarn or tow,the turbulent fluid action tends to cause the filaments to becomeinterentangled. The degree of intermingling of the filaments may dependupon many factors, such as the size, shape, stiffness, tension andlinear speed of the moving filaments, the geometry of the fluid jet, thetemperature, pressure and velocity of the treating fluid. On occasion,it may be desirable to supplement the bulking process with a fluidinterlacing treatment, such as described in Bunting et al. U.S. PatentNo. 2,985,995. One method of characterizing the degree of interlacing inthis patent is termed the hook-drop test.

The hook-drop test is based on the distance a weighted hook insertedthrough a yarn bundle can be lowered before the weight of the hook issupported by the resistance of the yarn to further passage of the hookdown the yarn. The result is calculated as 100 divided by this distancein centimeters so that greater coherency is indicated by higher values.The procedure for the hook-drop test is detailed in Bunting et al. US.Patent No. 2,985,995. The coherency factors for the bulky yarns in thisdisclosure have been obtained by this test.

The dyeing rates for feed and jet processed yarns are determined byanalyzing the dye baths or fibers. The amount of dye in the fiber isdetermined after dyeing for a short interval at a given temperature.Complete dye rate curves can be obtained by dyeing a number of separatesamples each for different lengths of time. For the purpose of thisinvention, however, the dye rate is defined as the amount of dyeabsorbed by the fiber in ten minutes at a given temperature. Each fibersample is dyed in a separate dye bath. The percent dye in the fiber maybe determined by ultraviolet spectral analysis of the dye bath or of asolution obtained by extracting dye from the fiber. The ratio by weightof dye bath to yarn is 400: 1.

Slightly different methods are used for acid-dyeable polymers, basicdyeable polymers and those which dye with neither acidic nor basic dyes.arns having basic sites in the polymer such as the polyamide yarns, 6and 66 nylon. are dyed at F. for ten minutes with 8% acetic acid and 4%Dupont Anthraquinone Blue SWF based on weight of fiber. AnthraquinoneBlue SWF is Acid Blue of the Colour Index, Society of Dyers andColourists and American Association of Textile Chemists and Colorists,1956. The percent dye in fiber is calculated from the percent in the dyebath based on light transmission at wave lengths of 595 millimicrons.The initial dye bath with a known amount of dye serves as the standardsample for calculating concentration of dye in unknown solutions afterdyeing. The dye baths, including the standard, are diluted two-foldbefore measuring transmission. The concentrations of dye in the bath arecalculated from percent transmission by the use of Lamberts Law.

Yarns having acidic sites in the polymer such as modified polyethyleneterephthalates containing 2% or more of a sulfoisophthalic ester aredyed using 4% Dupont Sevron Blue 56 (generic name, Basic Blue 4 andColor Index No. 51004) and 4% acetic acid for 10 minutes at the boil inthe absence of carriers. The percent dye in the fiber is calculated fromthe percent dye in the bath using the transmission at 660 rnillimicrons.The bath is diluted tenfold for this determination.

Yarns which do not have acidic or basic sites, such as unmodifiedpolyethylene terephthalate, are dyed with a dispersed color in theabsence of carriers. It is desirable to use a color which is sensitiveto physical changes in the fibers. The polymers with no acidic or basicgroups are dyed, therefore, with 4% Latyl Violet BN (generic nameDisperse Violet 27 in the Color Index) and 2% sodium lauryl sulfatedispersing agent based on fiber weight for 10 minutes at the boilwithout carrier to establish the dye rate. After drying, fiber samplesweighing 0.5 g. are analyzed for percent dye by extracting several timeswith chlorobenzene at 100 C. for about 5 minutes. The combined extractsare then diluted to a total volume of 100 ml. Analysis is made by usingan ultraviolet spectrophotometer at 580 millimicron wave lengths.

The stem treated yarns and the feed yarns are examined by standard X-raydiffraction techniques after relaxed boil oif. Methods for determiningorientation angle are described by W. A. Sisson in the Journal ofTextile Research, 7, 425 (1937) or Ingersoll, H. G., J. Appl. Phys. 17,924 (1946). For the purposes of this invention, fibers are mounted forX-ray examination with 0.015 g.p.d. tension applied to removesubstantially all crimp during exposure. The orientation angle isdefined here in terms of the aximuthal width of an intense equatorialdiifraction arc. The angle is the Width in degrees between the twopoints midway the peak intensity and the background intensity. Thisparameter decreases in value as orientation increases.

Higher temperature of the turbulent fluid tends to give higherorientation angles (low crystalline orientation). Orientation angles ashigh as 40 have been obtained by the process of this invention. It ispreferred that the treated yarn have an orientation angle greater thanthat of the feed yarn. Orientation angles for 6 nylon are obtained inthe range 13 to 35 degrees by varying the process condition. For 66nylon the orientation angle ranges from 13 to 40 degrees and forpolyethylene terephthalate homopolymer orientation angles are obtainedin the range 24 to 50 degrees. The basic-dyeable polyethyleneterephthalates obtained by copolymerization of terephthalate esters withsulfoisophthalic esters likewise deorient in this bulking process, andorientation angles of 22 to 50 degrees are obtained. Yarns fromcrystallizable polymers have greatly increased crystallinity aftertreating in the hot turbulent jet.

The surprising feature in the bulky yarns of this invention is thecombination of high bulk, high tenacity and low orientation (highorientation angle). Other known processes (e.g., British Patents 684,046and 735,171) give high tenacity even though the filaments aredeoriented, but these other processes result in yarns with filamentsstuck together, with no crimp, and without the random S and Z twist offilaments of this invention.

If the overfeed is kept low enough at any given set of processingconditions, uncrimped yarns with random S and Z filament twist may alsobe obtained by the process of this invention. These uncrimped yarns aresuperior to other heat-relaxed yarns since, in addition to the noveltwist, the filaments do not stick together, and they have very high dyerates and high tenacity.

Additional information may be obtained by studying low-angle X-raypatterns by the method of W. O. Statton (J. Polymer Sci. 22, 385 (1956),Crystallite Regularity and Void Content in Cellulosic Fibers as Shown bySmall Angle X-Ray Scattering). The low-angle pattern shows a higheramount of crystallite placement regularity in the At the same time thereis a great increase in the size of the long period. A typicalsteam-bulked 6-6 nylon yarn, for example, had a long period of 98 A.While the feed yarn had a long period of only 86 A. Higher temperaturesand longer exposures to hot fluids in the jets give greater longperiods. It is preferred that the treated yarn have a long period atleast 4 A. greater than the feed yarn. By the process of this invention,filaments of various polymers having long periods in the followingranges are obtained. 66 nylon, 75-100 A.; polyethylene terephthalate,95-140 A.; 6 nylon, -110 A.; copolymers of polyethylene terephthalate,-140 A.

According to this invention there are produced filaments havingoutstanding tenacity and very high dyeability, for example,poly(hexamethylene adipamide) having a long period of at least 90 A., atenacity (T of at least 3.0 and an orientation angle of at least(23.5-1.4; T poly(epsilon caproamide), said filament having a longperiod of at least 92 A., a tenacity (T of at least 2.5 and anorientation angle of at least (23.5-1.4 T poly(ethylene terephthalate),said filament having a long period of at least A., a tenacity (T of atleast 1.0 and an orientation angle of at least (47-40 T and copolymersof ethylene terephthalate containing less than about 10% combinedmonomers other than ethylene terephthalate and copolymerizable withethylene terephthalate, said fiiament having a long period of at least110 A., a tenacity (T of at least 1.0 and an orientation angle of atleast (28-23 T The following examples illustrate filaments of thisinvention and methods for preparing them. It is to be understood thatwhile they illustrate the use of certain synthetic polymeric yarnshaving certain cross sections these may be substituted by any otherpolymeric yarn or filament herein disclosed having any cross sectionsuch as circular, square, rectangular, fiat, star-shaped, or thosehaving three or more cusps and similar shapes. Likewise the denier,speed, temperature, take-up speed, and other considerations may varywidely within the limits given above.

All of the filaments of this invention illustrated in the followingexamples have completely random S and Z twist as described heretofore,and all the bulky yarns contain filaments which have both random S and Ztwist and in addition have a random, persistent, three-dimensional,non-helical curvilinear crimped configuration continuously along thefilament length as described above.

EXAMPLE I Three ends of a 1000 denier-68 filament-zero twistbright 6-6nylon (round filament cross section) were passed simultaneously throughthe jet of FIGURE 2 using the process of FIGURE 1. The yarn passed overa feed roll at 110 y.p.rn. just before entering the jet. It was bulkedwith turbulent superheated steam in the jet at 500 F., the steampressure being 45 p.s.i.g. As it emerged from the jet, it passed over atake-up roll at 76 y.p.m. so that the overfeed rate was 40%. The yarnwas cooled in the surrounding air, and collected as a piddle cake. Theabove feed yarn was obtained by cold drawing 6-6 nylon 400% (5XAdditional 1000 denier feed yarns were obtained by drawing speciallyprepared yarns at lower draw ratios (4X, 3X, 2.5x, and undrawn). Each ofthese IGOO-denier feed yarns was steam bulked under the same conditionsas described forthe 5X drawn yarn above. The treated yarn properties aregiven in Table II. The undrawn yarns tended to draw in the turbulentsteam rather than contracting; the bulked undrawn yarns, therefore, hadhigh filament crimp elongation but the denier decreased. The unusualcombination of high tenacity and high dye rate for a jet-bulked productis shown in Table I. The dye rate of the bulked yarn is many timesfaster than the dye rate of a 2.5x drawn feed yarn, but the tenacity isstill almost equivalent to that of a 5 X drawn feed yarn.

' 55 Table I DYE RATES AND PHYSICAL PROPERTIES OF 63-6 NYLON YARNS 155drawn 6-6 nylon. The processing conditions were adjusted to give a widerange of useful bulked products. The effect of processing conditions onthe geometry of the bulked products is shown in Table III. At low overca Properties Ofboilcd OII filaments feeds, the increase in yarn denier(after exercise and Dmwmtio and type ggg g boil-off) was greater thanthe machine overfeed. For Ofyarn r i pgs y, g i M g example, 37% machineoverfeed gave a boil-off yarn t I v e a 0 ,5 31, gp denier lncrease of89%. At high overfeeds, the actual yarn denier increase tended to beless than the machine 2.5x med yam 0 53 135 28 10 overfeed because ofthe unstable loops which pulled out 252 i253 8- 2 8; 38 when the yarnwas exercised. At higher speeds the crnnps 5X f d g jjjjjjj: 63 38 perinch developed in the process was less than at low X 73 20 speeds (Nos.5 and 6). Single ends or triple ends were passed through the jet withequal success (Nos. 7 and 8). Table II EFFECT OF DRAW RATIO ON STEAMBULKING OF 6-0 NYLON YARNS 1 Bulked yarn denier Yarn denier increase,Filament crimp percent elongation, percent Draw ratio of iced yarn Afterten- Alter tens. Piddlod After tens. After tens. Piddled sioning andboil-oil 407i}, ogerand boil-011 Piddled and boil-011 4, 468 4, 45s 5,05s e9 32. 1 42. 9

4, 720 4, 720 5, 517 57 so so. 0 59. 1

4, 380 4, sso 4, 905 4s 64 37. 3 so. 4

1 All yarns were run with 3 ends of 1000 denier through jet. Total feedyarn denier was therefore 3000. All yarns were run with 40.5% machineoverieed, at 500 F., p.s.i.g., and 110 y.p.m. feed speed.

Bulked yarns having high filament break elongations ended to pillreadily in carpets as shown in FIGURE 10. The pilling index is a numberwhich Was determined by subjective rating using a test panel. An indexof 5 is completely unacceptable, index of 3 is borderline acceptable,and index of 1 indicates no pilling. The carpet samples were testedtogether in a tumble-pilling device (a converted home laundry dryer) for20 hours using wooden blocks and pieces of rubber sheeting to give thepilling action. The test was run at room temperature. The ratings shownin FIGURE 10 indicate that elongations greater than 200% gaveunacceptable carpets.

iniilar pilling tendencies were noted for yarns of high elongation inknitted, woven materials, and other constructions. Yarns having lowfilament break elongation, on the other hand, gave fabrics with littleor no pilling. The preferred non-pilling yarns had break elongation lessthan 200%.

EXAMPLE II Higher pressures tended to give higher crimps per inchbecause of the greater throughput of heat in the jet. Monofilament waseasily processed through the system as shown in No. 10. Hot air wasequally efiective and produced good bulk yarns as shown in No. 11. Thesuperior bulking quality of Y over round cross section is shown in No.12 and No. 13. The yarn with Y cross section increased 99% in denierwhile the yarn with round cross section increased only 67%. The percentsincrease in filament denier in Nos. 4, 7, 8, 12, and 13 are 38, 70, 29,11, and 7, respectively. Birefringence patterns for items 7, 8, 9, 10,and 12 show lines of constant retardation parallel to the axes of thesefilaments throughout the filament lengths. These products when viewedunder reflected light in a non-polarizing microscope are seen to be freefrom cross-sectional distortions throughout their lengths, that is,there were no grooves, dents, or

A number of bulked yarns were prepared from 4X bulges.

Table III EFFECT OF PROCESSING CONDITION ON GEOMETRY OF BULKED YARNSFROM 4X DRAWN (5-6 NYLON [All feed yarns were BR* luster except asnoted] Feed yarn Processing conditions Bulked product (after tensioningand relaxed boil-oil) Machine Feed Bulked Percent Fiber Yarn 1 No. ofTwist Cross section Jet fig. overtced, speed, Temp, Press, yarn increasecrimp Crimps/ denier/end iils. percent y.p.m. F. p.s.1.g. denier 1n yarnelong, in.

denier percent 158 Y (2.2MR)* 2 37 200 603 108 4, 340 59 10.7 158 Y (2.2R) 2 200 610 108 5, 169 125 11.1 158 Y (2.2MR).- 2 150 200 610 108 5,188 126 12. 0 158 Y (22MB) 1 100 50 400 110 6, 945 202 131 10. 5 138 "Y(2.2M R) 2 100 200 575 85 4, 729 137 86 14. 9 138 Y (2.2M R) 2 100 400600 S5 4, 071 104 82 i). 8 51 R* 1 100 50 460 100 1, 760 126 53 10. 6 511 100 50 450 100 5, 979 158 101 18. 2 08 2 40. 5 110 500 45 4, 600 55 378. 9 T1 1 75 50 580 90 I18. 3 22 110 18.0 1 76 50 353 3 85 5, 395 15221.0 68 2 41 110 500 45 5, 022 07 5S) 7. 9 68 0.414..." Y (22MB) 2 41110 500 45 5, 975 99 110 11.1

1 A single end of yarn was used in all cases except as noted. 2 Threeends of this yarn were used. 3 Air was used as the turbulent fluid. 4These feed yarns were SD* Luster. *MR means modification ratio. R meansround. BR means bright. SD means semi-dull.

All entries were prepared using steam as the turbulent fluid except asnoted.

1 7 EXAMPLE HI A number of different polymeric synthetic yarns wereprocessed as shown in Table IV. In each case a bulky product wasobtained. Some of the yarns had unstable loops which were pulled out byexercising, but the individual filaments when removed from the yarn hadcrimp which was stable outside of the yarn bundle. The considerableincrease in bulk which was obtained is shown by the increase in yarndenier and fiber crimp elongation in Table IV.

All of the bulked yarns had filaments with random, three-dimensional,non-helical, curvilinear crimp, which was independent in each filamentin that it did not coincide with adjacent filaments.

I8 detergent solution followed by rinsing and drying in a hot-air tumbledrier.

Fabric properties are tabulated in Table V.

Table IV PROCESSING CONDITIONS AND CHARACTERISTICS OF BULKED YARNSPREPARED FROM A VARIETY OF SYNTHETIC POLYMERIC FIBERS Feed yarnProcessing conditions Bulked product (as produced) Yarn .Tet Mach. Feed7 Bulked Percent Fiber Orimps Polymer den. No. of Twist Den of overfeed, speed, Temp, Press, yarn inc. 1n Den. crimp per 1 end of fils. per01 fig. percent y.p.m. F. p.s.i.g. den. yarn per fil. elong., inch den.percent 1. Polyethylene terephthalate 1, 100 250 4. 40 1 50 110 495 901, 620 47. 3 4. 44 43. 9. 2. Pclyacrylonitrile- 40 0. 3Z 2. 50 1 26 38408 48 378 26. 0 2. 58 52.5 10. 1 3. Cellulose acetate--- 1,800 88 2520.4 1 60 200 400 80 2, 686 29.0 18.9 47. 5 9.8 4. Viscose 2, 700 150 018.0 1 97 50 415 95 3, 384 24. 0 17. 5 36. 5 7. 2

1. A single end of yarn was used in each entry except entry 2 in whichcase three ends of this yarn were used. 2. The feed yarns in entries 1and 2 were SD Luster and in entries 3 and 4 the feed yarns were B RLuster. 3. A

11 entries were prepared using steam as the turbulent fluid.

EXAMPLE IV The superior bulk of steam bulked yarns in carpets wasdemonstrated by preparing carpets with staple yarn and carpets withsteam bulked yarn in which the polymer was 6-6 nylon. A three-plycotton-system staple yarn prepared from 15 d.p.f. nylon was tufted toprepare carpets having several different weights of yarn in the pile(depending upon number of stitches per inch). All carpets had 0.43" pileheight. Similarly, steam-bulked yarns were put into tufted carpets. Thesteam-bulked yarn was prepared from one end of 2000 denier-136filament-.38Z-r0und-bright-6-6 nylon using 100% overfeed, 200 y.p.m.,575 F., and 90 p.s.i.g. The work'required to compress carpets of thesteam-bulked yarn and of staple yarns to 10 p.s.i. was determined usingan Instron testing machine. The work required to compress 4-squareinchareas of staplecarpets of various weights and steam bulked carpets ofvarious weights is shown in FIGURE 11. The steam-bulked yarns were muchfirmer to the hand in carpets of identical weight and this observationwas confirmed by the Instrom tests. Consequently, carpets with to lessyarn were needed for steam-bulked continuous-filament yarns to get thesame performance as staple carpets. In FIGURE 11, Curve A shows the workrequired to compress carpets of various weights prepared from stapleyarns. The Total take-up in FIGURE 11 is the weight of tufted yarn in asquare yard of fabric and does not includ the jute backing. Curve Bshows the work required to compress steambulked continuous-filamentyarns in carpet.

EXAMPLE V Item A.840-140- /2Z bright nylon yarn was processed with a jethaving a needle and venturi as in FIGURE 2. An overfeed of 44.6%, a feedspeed of 150 y.p.m., a steam temperature of 440 F., and a steam pressureof 85 p.s.i.g. were used.

Item B.840140 /2Z bright filament nylon unbulked control yarn.

These two yarns were knit on a 6-cut circular knitting machine(Jacquard) using a half-cardigan stitch. Fabric was finished by scouringat the boil for 15 minutes in a Item A shows a marked improvement overItem B in bulk and opacity. The fabric has a pleasing, wool-like handand is scroopy and resilient in hand as compared with the unattractivehand of the control.

EXAMPLE VI A bulk yarn was prepared from 2700 denier-180 filament-zerotwist 66-nylon by passing the yarn through the jet shown in FIGURE 2,using steam at 515 F., the yarn being fed at 200 y.p.m. and with anoverfeed of 100%. This yarn Was put into an upholstery construction. Thebacking yarns were high twist 20/2 cotton. The filling yarns were 12/2cotton. The weaving construction was 18.7 pile ends per inch, 56 backends per inch, 17 picks per inch, and the reed width was 55 /2 inches.The gauge wire was 0.10 inch. A similar upholstery material was preparedfrom the uncrimped yarn. This unbulked material required 21 picks perinch to get the same optical cover as was obtained using the bulk yarn.

EXAMPLE VII A nylon tow of 80,000 denier and 20,000 filaments was fed at2 yards per minute to a jet similar in cross section to FIGURE 2. Thisjet, however, was elongated in a direction perpendicular to the plane ofthe cross section so that the yarn opening 119 was a slot four incheswide, and orifice member 117 was provided with an orifice in the shapeof a similar slot, likewise four inches in width. The orifice angle was30. The tow was fed to the jet in a flattened ribbon form so that allparts of the yarn opening and jet orifice were filled in a substantiallyuniform fashion. The turbulent fluid was 70 p.s.i.g steam, heated 19EXAMPLE VIII A IS-denier 66-nylon monofilament yarn prepared at a feedspeed of 50, an overfeed of 76%, using steam at a pressure of 90 p.s.i.at a temperature of 580 F., was

at time, these yarns may be produced with curvilinear crimp. The amountof crimp and the dye rate each increased as the jet temperatureincreased. The data from this experiment are shown graphically in FIGURE9 where line A knit into a full-fashioned heer hose using a 60-gaugerepresents autoclaved yarn and line B refers to bulked yarn knittingmachine set at 50 courses per inch. A similar prepared in a steam jet.

Table VI Dye rate Filament tensile properties (boiled ofi) acid dye Orenta- Yarn treatment: (percent tion 1 absorbed Ten., Elong, M1, Denierper angle, in min. g.p.d. percent g.p.d. filament deg. at 140 F.)(d.p.f.)

Feed yarn 0. 42 6. 0 36 29 15. 8 13.0 Jet, 275 F., 40% 0Verleed 0. 55 6.5 38 25 15. 7 13. 3 Jet, 325 F., 40% overl'eed 0.71 7.1 45 24 15. 3 14.4 Jet, 450 F., 100% overteed 1. 43 5. 0 98 8. 5 19. 7 20. 8 Autoclave,275 F., minutes,

H2O 0.83 5. 7 108 26 14. 8 14. 4 Autoclave, 325 F 15 m utcs,

H1O 1. 1. 4 23 21 18. 7 1S- 6 1 Measured using 100 diflraetion spot.

hose was constructed of the unmodified monofilament. EXAMPLE X Thegarment made from the modified rnonofil showed a subtle crepe-liketxeture and a subdued luster. It also showed a moderate amount ofstretchiness, improved form fitting characteristics, and freedom frombagging at the knee as compared with the unmodified control.

EXAMPLE IX A single end of a continuous-filament poly(epsiloncaproamide)yarn was bulked under several difierent conditions using steam in thejet of FIGURE 2. The feed yarn was 4200 denier-224 filament-zero twistbright yarn. Each of the yarns was processed with 200-yards-perminutefeed speed and 80 p.s.i. steam pressure. Additional processing data anddescription of the product are shown in Table VII. Each of the jetprocessed yarns was crimped, but the most desirable crimp was obtainedafihe highest temperature. The data show again that tenacity wasmaintained at a relatively high level as the dye rate increased. Whenthe same feed yarn was autoclaved at 275 F., a much lower tenacity wasobtained at a comparable dye rate. At still higher autoclavetemperatures, such as 325 F., the yarn melted. It was not possible toobtain strong yarns in the autoclave with dyeability similar to that ofthe 460 F. or 530 F. jet-bulked yarns.

Table VII Dye rate Filament tensile properties (boiled oti) acid dyeOrienta- Yarn treatment (percent tion 1 absorbed Ten, Elong., Mi, Denierper angle, In 10 mm. g.p.d. percent g.p.d. filament deg. at 140 F.)(d.p.f.)

Feed yarn 0. 74 8. 1 27 18. 8 12. 0 Jet, 415 F., 75% overfeed 1. 98 6. 858 14 20. 5 13. 3 Jet, 460 F., 75% overfeed 2.14 6. 4 8O 10 22. 5 Jet,530 F., 125% oyerieed 2. 21 3. 8 128 7. 9 27. 2 18. 9 Autoclaved 275 F.,15 minutes,

1 Measured using 100 diffraction spot.

the same time, the dye rate with an acid dye (Du Pont EXAMPLE XIAnthraquinone Blue SWF) increased from 0.42% in 10 minutes for the feedyarn to 1.43% for the 450 F. bulked yarn. The orientation anglesincreased from 13.0 degrees to 20.8 degrees as the temperature increasedto 450 F. Other samples of the same feed yarn were treated by immersingin water for 15 minutes at 275 F. or 325 F. in a sealed autoclave. Therewas a drastic reduction in tenacity to 1.4 grams per denier in theautoclaved sample prepared at 325 F. The dye rate for the autoclavedyarn increased to 1.20% for the sample treated at 325 F. The autoclavedyarns had no crimp even though the orientation angle increased greatly.The data show that the yarns of this invention have the rare com- Asingle end of continuous-filament yarn spun from polyethyleneterephthalate was bulked using the jet of FIGURE 1. The feed yarn was a70-denier-34 filamentzero twist semi-dull yarn with round filament crosssection. Each of the yarns was processed as indicated in Table VIII,using 500 yards per minute feed speed and 55 p.s.i. steam. Only moderatecrimp was obtained at 500 F., but at the higher temperatures shown, 610F. and 660 F excellent crimp was obtained, and the dye rates were verygreatly increased. The bulked yarns were dyed with Latyl Violet BN, adispersed dye, in the absence of carrier. Autoclaved samples, on theother hand, had greatly reduced dye bination of high tenacity and highdye rate. At the same rate after treatment at 275 F., 325 F., or 350 F.as

21 indicated in Table VIII. The orientation angles increased for theautoclaved yarns and for jet-treated yarns, but only the jet-treatedyarns had the combination of good crimp, high dye rate, and hightenacity. The jet of FIGURE 1 is described in detail by John N. Hall inUS. Patent No. 5

22 to a steam jet at 393 y.p.m. with an overfeed of 40% through a jetsimilar to FIGURE 1 of Hallden, Jr., et al., U.S. Patent No. 3,005,251.The steam supply to the jet was superheated to a temperature of 460 F.at a pressure of 7-1 p.s.i. The yarn was wound up at a speed 2,958,112.of 280 y.p.m. The treated yarn picked up more than Table VIII Dye rateFilament tensile properties (boiled ofl) dispersed Orienta- Yarntreatment dye (percent tion 2 absorbed Ten., Elong., Mi, Denier perangle, in 10 min. g.p.d. percent g.p.d. filament deg.

at boil) (d.p.f.)

Feed yarn 1. 02 4. 7 48 59 2. 2 Jet, 500 F., 42% overfeed 1. 06 4. 2 332. 5 24.1 Jet, 610 F., overieed 1. 41 3.1 127 16 3. 2 .Tet, 660 F., 125%overieed 2. 32 2. 8 126 21 3. 2 43. 6 Autoclave, 275 F., 15 minutes,

11 0 0.25 4. 8 60 65 2. 2 Autoclaye, 325 F 15 minutes,

H1O 0. 26 4. 5 53 54 2. 3 Autoclave, 350 1 minutes,

1 Mi is initial modulus which is the slope of the straight line portionof stress-strain curves beyond the point of crimp removal (load ingrams/denier vs. fractional elongation).

2 Measured using difiraction spot.

EXAMPLE XII A modified poly(ethylene terephthalate) yarn having 2.0%sulfoisophthalic ester in the polymer was treated as shown in Table IX.The feed yarn was a single end of 70 denier-50 filament-zero twistsemidull yarn having filaments with triangular cross section. All of theyarns were processed in the jet at 500 y.p.m. and 55 p.s.i. steampressure. Moderately crimped filaments were obtained at the lowertemperatures. Very highly crimped filaments were obtained from the jettreatment at 500 F. The bulked yarns were dyed with basic dyes and thedye rate increased very greatly for the 500 F. samples. This increase indye rate was obtained without appreciable loss in tenacity. On the otherhand, yarns which were treated in the autoclave, as shown in the table,had much lower dye rates and 45 were not crimped.

twice as much basic dye as the untreated yarn when dyed With Du PontSevron Blue 5G. The treated yarn, in fact, had improvement in dye rateover the untreated yarn. There was no crimp in the jet processed yarn,but the individual filaments possessed random S and Z twist throughouttheir length. This improvement in dye rate achieved with the treatedyarn is not specific to the conditions used in this given dyeingprocedure. Numerous other basic dyes had equivalent improvementincluding Du Pont Brilliant Green Crystals, Du Pont Fuchsine, and SevronBlue BGL. Similar improvements in dyeability have been achieved withfabrics prepared from the yar-ns using b'ath-to-fabr-ic ratios as low as15:1 and as high as 500:1.

EXAMPLE XIV Two ends of a 1020 denier-68 filamentfizZ twist-semi- T ableIX Dye rate Filament tensile properties (boiled ofi) basic dye Orienta-Long Yarn treatment (percent tion 2 period, absorbed Ten, Elong, Mi,Denier per angle, deg. deg. A. in 10 min. g.p.d. percent g.p.d. filamentat boil) (d.p.f.)

Feed yarn 1. 26 3. 2 61 44 1.5 18. 5 99 Jet, 300 F., 19% overload--.0.90 3. 3 52 48 1. 6 22. 7 98 Jet, 400 F., 35% overt'eed 1. 24 2. 8 5943 1.6 Jet, 500 F., overfeed- 2. 50 2.6 91 25 2.0 24. 7 122 Autoclave,275 F., 15 min- 1 Mi is initial modulus which is the slope of thestraight line portion of stress-strain curves beyond the point of crimpremoval (load in grams/denier vs. traetional elongation).

2 Measured using 100 diffraction spot.

EXAMPLE XIII Filament yarn (70 denier-50 filament-zero twist, Y crosssection) of poly(ethylene terephthalate) modified with 2.0% of asulfonated derivative of isophthalic acid dull 6-6 nylon (tri-loba-lcross section) were passed simultaneously through the jet of FIGURE 2using the basic process of FIGURE 1. The two ends of yarn were passedover individual feed rolls at and 186 to provide dyeability with basic(cationic) dyes, was fed 75 y.p.rn. just before entering the jet. Thecombined ends were bulked with turbulent superheated steam in the jet at550 F. The steam pressure was 70 p.s.i.g. As the composite yarn emergedfrom the jet, it passed over a take-up roll at 95 y.p.m. so that theoverfeed rates for the two individual ends were 56% and 95%,respectively. The yarn was cooled in the surrounding air and collectedas a piddle cake. The resultant product was a bulked yarn that whentwisted to high twist-levels, for example, 7 turns per inch, exhibitedmuch greater bulk than a comparable double-end structure processed atequal overfeeds.

EXAMPLE XV A single end of 1800 denier-88 filament-zero twist brightcellulose diacetate yarn (Y cross-section filaments) was passed throughthe jet of FIGURE 1 using steam at 288 F. and 16 p.s.i.g. The feed speedwas 150 y.p.m. and the overfeed was 40%. A highly bulked product Wasobtained. It was wound up on cones at 4 grams tension. The resultingproduct had a bulked yarn denier in the relaxed state of 2100, a yarncrimp elongation of 20%, and a tensioned yarn denier of 1750 (whenloaded to 0.1 g.p.d.). The average number of crimps per inch in thefilaments was 12, and the tenacity of the filaments was 0.8 g.p.d. Thefilaments had a very pronounced random twist, being alternately S and Zand having a random number of turns between twist reversals and randomangles of twist. The total S and Z twist was about 20 turns per inch,which corresponds to an average twist angle of about 10. There was atleast one S turn and at least one Z turn per inch of filament which hasa twist angle averaging at least 10.

Filament twist may be easily determined using the American Optical BakerInterference Microscope using techniques specified by the manufacturerin the operating manual for this microscope. Several individualfilaments are removed from a sample of yarn, mounted on clean microscopeslides under only sufiicient tension to hold the filaments substantiallystraight, and visually evaluated for twist at 30 to 150-powermagnification (depending upon the size of filament) while traversing ameasured distance along a filament. The number of full turns of S twistand of Z twist are counted, and the effective twist angle of each fullturn is determined.

EXAMPLE XVI Yarns of linear polypropylene were bulked using saturatedsteam in the jet of FIGURE 2. The processing conditions for threedifferent yarns are shown in Table X. The properties of the feed yarnsand of the bulked yarns are also shown. There was considerable filamentshrinkage during processing. This is indicated by the tensioned yarndenier after bulking and the denier of the feed yarns. The long periodincreased in a manner similar to that of poly(hexamethylene adipamide)and poly(ethylene terephtlialate). The filaments had random twist asdescribed hertof-ore, and undistorted cross sect-ion. The roundfilaments had uniform cross-sectional configuration throughout in thatthere were'no dents or grooves in the filaments. On the other hand,conventional twist heat-set bulked yarns or stutter-box yarns preparedfrom round filaments had a considerable amount of deformation in thesurface of the fibers after bulking.

The filaments crimped in accordance with this invention had a random,three-dimensional, crimped configuration and a random alternating twistwith effective twist angles in the full turns, measured as above,ranging from 4 to 18. There was at least one S turn per inch and atleast one Z turn per inch of filament having an effective or averagetwist angle of at least 241 Table X BULKED LINEAR POLYPROPYLENE YARNSNo. 1 No. 2 No. 3

Feed Yarns: 1

Number of yarn ends fed to jet 3 3 2 Denier per end 300 275 640 No. offilaments per end 20 23 23 Luster Bright Semi-dull Semidull Crosssection Round Trilohal Trilobal Tenacity (g.p.d.) 4. 5 517 5. 4

Break elongation (percent) 120 35 40 Initial modulus (g.p.d.). 201 51Long period (A.) 116 122 122 Processing conditions: 2

Steam temperature F 315 295 315 Steam pressure (p.s.i.g.) 40 65 PercentOverieed 60 80 Bullred yarn:

Bulked yarn denier (13 YD) 1,340 1, 042 1, 628

Tensioned yarn denier ('IYD). 1,055 928 1, 445

Yarn crimp elongation (YCE). 27 13 13 Crimps per inch 10 10 8 3. 2 '1. 94. 0 153 41 40 Initial modulus (g.p.d.) 12 29 19 Long period (A.) 130130 1 All feed yarns had zero twist; tensile properties are forboiled-oil single filaments.

2 All yarns fed to jet at y.p.m. B Tensile properties are for boiled-oilsingle filaments.

EXAMPLE XVII Heavy denier poly(hexamethylene adipamide) yarns wereprocessed using the conditions described in Table XI. The processdepicted in FIGURE 1 was modified by using two canted rolls in place offeed rolls 33 and 34. These rolls were used to heat the yarn before itpassed into the jet. The rolls had an average diameter of 3%. inches andwere separated slightly. The feed yarn followed a figure-eight patternaround the two rolls. There were 4 to 7 wraps around each roll asindicated in the table, the rolls being heated in an air chest which wasprovided with electrical resistance heaters. The yarns were passedthrough an impingement type jet similar to the one described and shownin FIGURE 1 of Hallden et al., United States Patent No. 3,005,251.

Superheated steam was fed into the jet from a manifold which completelysurrounded the jet except for the feed and exit ends. In one process asingle end of 1020 denier- 68 filament-0.5Z twist-semi-dull nylon withtrilobal cross section in the filaments was used to prepare a bulkedyarn having a tensioned yarn denier of about 1300. In operatingcontinuously over a period of several days, the tensioned yarn deniersfell within the range 1298 to 1336. Other property ranges are shown inTable XI. By a similar process, three ends of the 1020 yarn were passedthrough a jet of similar construction. The tensioned yarn denier of thisproduct was about 3700. Over a period of time the range was 3644 to3753. The above yarns were Wound on cones rather than being piddled tothe cans described in FIGURE 1. The coning tensions were 50 to 150 gramsfor the 1300-denier product and 75 to 225 grams for the 3700-denierproduct. Specific volumes as determined by the cylinder bulk testdescribed heretofore ranged from 8.1 to 8.5. On the other hand,poly(hexamethylene adipamide) staple yarns had specific volumes of 5.6,and continuous filament stuffer box yarns had specific volumes of 6.5 to7.3. Furthermore, these filaments did not have the random twist of thejet processed yarns described here. The jet-bulked yarns were found tobe very excellent carpet yarns, and much less yarn was required with thejet-bulked yarns than with staple yarns to prepare a carpet with goodresistance to compression. Carpets of poly(hexamethylene adipamide)staple required at least 25% more yarn to produce carpets of similarcompressional quality. The above process may be modified by using brightyarns instead of semi-dull yarns. These bright yarns provide bulkedproducts which are excellent upholstery yarns.

The yarns of this example had pronounced random varying alternating Sand Z filament twist. A total of 7 to 10 turns S and Z twist per inch offilament were measured by visual examination as in Example XVI. Theangles of separate turns of twist were in the range of 4 to 40, with anover-all average twist angle of about 9. Hence, the angle of filamenttwist was highly erratic random, completely independent of yarn bundletwist. The angle varied randomly and continuously along the filamentlength with a random number of twist reversals per inch and a randomnumber of turns between twist reversals. There was at least one S turnand at least one Z turn per inch having an average twist angle in excessof 5.

26 EXAMPLE XVIII Another modification of the process of FIGURE 1consisted of impinging the yarn, as it emerged from the jet, on a movingscreen. The moving screen was traveling at a much slower speed than theyarn as it emerged from the jet. As the yarn moved away from the jet onthe moving screen, it cooled and the crimp became very stable. After theyarn had traveled far enough on the moving screen to have cooledadequately, it was passed over a takeup roll as in FIGURE 1 and then toa windup. Yarns which were bulked by this process included Table XIIBULKED YARNS FROM JET AND SCREEN PROCESS No.1 No.2 No.3 No.4 No.5

Feed Yarn:

Polymer 6-6 1 6-6 2 2GT/SI 2 2GT/SI 3 HPXG-T 98/. 02) (965/035) Denier70 7O 78 150 Number of filaments. 13 34 50 50 34 W1 0. 5Z 0. 5Z 0 0 0.5Z Lustcr Semidull Semidull Scmidull Semldull Scmidull Cross section.Trilobal Trilobal Trilobal Trilobal ound Tenacity (g.p.d.) 4 4. 9 6. 2Break elongation (percent) 4 44 54 Initial modulus (g.p.d. 4 14. 5 14.7Dyeing rate (percent/i0 m 1. 05 5 1. 45 Long period (A.) 75 80Processing conditions:

Feed speed (y.p.n.) 1,000 566 Steam temperature 550 556 Steam pressure(p.s.i.g 40 38 Yarn speed on screen (3 40 33 Takeup roll speed (y.p.m.750 388 Percent overfecd, Iced roll to up r0 33 47 Windup speed (y.p.m.)790 407 Bulked yarn (boiled-011):

Bulked denier (BYD)- 72 112 Tensioned denier (TYD) .r 48 80 Crimpelongation (YOE), percent-.. 50 40 Crimps per inch 31 25 Tenacity(g.p.d.) 4. 5 4.3 Break elongation (percent) 65 70 Initial modulus(g.p.d.). 8. 8 11.8 Dyeing rate (percent/10 min.) 5 3.15 5 2. 57Specific volinne (ca/g. at 3.1 p.s.i.) 6. 5 6.5 Long period (A) 89 96'6-6 is poly (hexamethylcne adipamide).

2 2 GT/SI is a copolymer 0fpo1y(e thylcnc terephthalate) and the sodiumsalt of poly(ethylene sulfoisophthalate). the mole fraction of therespective constituents being indicated in parentheses.

3 HPXGT is the polyester derived 4 Single filaments, boiled-cit. 5 Aciddyeing rate. 6 Basic dyeing rate.

Table XI BULKED HEAVY DENIER a-s NYLON Feed yarn: 1

Number of yarn ends fed to et 1 3 Denier per end 1, 020 1,020 No. offilaments per end 68 68 Twist per end 0. 52 0. 52 Luster Semi-dullSerm-dull Cross section. Trilobal Trilobal Tenacity (g.p. 4. 8 4. 8Break elongation (percent) 72 72 Initial modulus (g.p.d.) 21 21 Dyeingrate (percent/10 min.) 0. 65 0. 65 Long period (A.) 73 73 Processingconditions: 1 Prelileater, number of wraps on each 7 4 en Preheatertemperature C F.) 410 350 Feed speed (y.p.m.) 380 250 Manifoldtemperature F.) 509 473 Manifold pressure (p.s.1.g.) 95 Percent overfeedto takcup roll 81 85 Takeup roll speed (y.p.m.) 210 135 65 Coning speed(y.p.m.) 241 155 lgloning tepsion (grams) 50-150 75-225 Bul ed arn:

Bullied yarn denier (B YD) 1, 040-2, 020 5, 038-5, 903 Tensioned yarndenier (TYD) 1, 298-1, 336 3, 644-8 753 Yarn crimp elongation (YCE),percent 50-51 58-57 Orimps per inch 19-21 15-18 Tenacity (g.p.d.)-.3.0-3.1 3.3 Break elongation (percent)- 78-93 65-67 Initial modulus(g.p.d.) 6. 2-5. 6 8. 3-9. 0 Dyeing rate (percent/10 min.) 1 78-1. 97 1.46-1. 51 Specific volume (cc./g. at 3.1 p.s.1.) 8. 1-8. 5 8. 3-8. 4 Longperiod (A.) 92-93 83-87 1 Tensile properties are for single filaments, boiled-oil.

irom trans-1,4-bis-(hydroxymethyl)cyclohexane and terephthalic acid.

poly(hexamethylene adipamide), basic dyeable poly- (ethyleneterephthalate) copolymers having 2 to 3 /2 mol percent of the sodiumsa-lt of poly(ethylene sulfoisophthalate), and a polyester oftrans-1,4-bis(hydroxy methyl)cyclohexane and terephthalic acid. Thebulking of these yarns is described in Table XII. The denier of thestarting yarn and the tensioned yarn denier of the products indicatedthat filament shrinkages were at least 12% in all of the products.

EXAMPLE XIX A fiber of a polymer of acrylonitrile having 93.65% byweight acrylonitrile, 5.98% methylacrylate and 0.37% styrene sulfonicacid was bulked using the jet of FIG- URE 1. The feed yarn was 900denierfilament-0.3Z twist-semi-dull fiber with dogbone-shaped crosssection in the filaments. The boiled-01f tensile properties of singlefilaments before bulking were as follows: 3.1 g.p.d. tenacity, 34%elongation, and 33 g.p.d. initial modulus. This yarn was processed usingthe screen described in EX- ample XVIII. The steam temperature in thejet was 510 F. and the pressure was 75 p.s.i.". The yarn passed into thejet at 495 y.p.m. and impinged on the screen as it emerged from the jet.The yarn was carried along the screen at 30 y.p.m. for about 24 inches.Then the yarn was continuously removed from the screen and passed over atakeup roll at 305 y.p.m. Finally, the yarn was collected by piddling.The overfeed from the feed roll to the takeup roll was 62%. The productwas a very bulky yarn having bulked denier of 1848, a yam crimpelongation of 48%, a tensioned yarn denier (at 0.1 g.p.d.) of 1249, andhaving 11 crimps per inch in the filaments. The boiled-off filaments hada tenacity of 2.7 g.p.d., 33% elongation at break, and an initialmodulus of 35 g.p.d. The excellent bulk of this product was demonstratedin the cylinder bulk test. Before boil-off, the yarn bulk was 13.2 cc.per gram, and after boil-01f, the yarn bulk was still 10.8 cc. per gram.

EXAMPLE XX A yarn of a polyester copolymer of 98 mol percentpoly(ethylene terephthalate) and 2 mol percent of poly- (ethylenesulfoisophthalate), previously designated as ZGT/SI, with filaments oftrilobal cross-section about 1.9 modification ratio was melt-spun anddrawn on heated rolls, at about 330 F. in an air chest. The drawn yarnwas delivered from the draw rolls at speeds in excess of 1000 y.p.m. toa jet device in which two streams of air at about 65 p.s.i.g. and 570 F.and impinged upon the traveling threadline in its pasasgeway. The fluidstream served to pull the yarn from the draw rolls, heat the yarn, Whipthe filaments randomly about, and deposit the yarn on a slowly movingscreen surface. The treated yarn was allowed to cool in a tensionlessstate on the moving surface and was then withdrawn to a windup.

The continuous-filament yarn passing from the draw rolls to the treatingjet was 83-denier SO-filament yarn with about 3.0 g.p.d. tenacity and38% break elongation. The net rate of overfeed to the jet was 50%. Thetreated yarn was 125 denier with about 1.7 g.p.d. tenacity andapproximately 70% break elongation. The treated yarn was bulky, withrandom, three-dimensional crimped configuration of the filaments. Theyarn, however, was highly interlaced and coherent, having a coherencyfactor about 56.

The individual filaments had alternate S and Z twist throughout thetreated length, with a random number of twist reversals per inch and arandom number of turns of twist between reversals and at least one S andone Z turn per inch of over 5 average angle. By microscopic examinationof filaments, for example, an average of 7 full S twists and 5 Z twistsper inch were observed along the lengths of filaments.

The dye rate increased from 1.4 (percent per 10 min.) to 3.68% as aresult of the fluid treatment. Therefore, the dye rate-tenacityrelationship D T /D T equalled 1.45.

Fabrics woven from the bulked yarn had a dry pleasing hand, lesstendency toward pickiness and pilling, and lower fabric shrinkage thanfabrics of untreated yarn.

EXAMPLE XXI A continuous multi-filarnent 66 nylon yarn was meltspun andcontinuously drawn on rolls in an air chest heated to about 435 F. Theyarn was composed of 34 filaments of trilobal cross-section with 1.9modification ratio. The drawn heated yarn was fed at high speed to a jetin which the filaments were impinged with an air stream at 95 p.s.i.g.and 580 F. The treated yarn was discharged onto a slowly rotating screenwheel, allowing the filaments to separate from the air stream, where itwas conveyed in a tensionless state before being withdrawn to a packagetake-up at a speed in excess of 1000 y.p.m. The yarn overfeed to the jetwas of the order of 14%.

The treated yarn had a crimpy bulk. The denier was 85 and the aciddyeing rate was 2.79 (percent/ 10 min), almost 100% greater than the1.40 dyeing rate of the drawn yarn fed to the jet. The filaments wereinterentangled, as evidenced by a coherency factor of approximately 8.The individual filaments were highly twisted, with approximately 4 S and3 Z turns, of at least 5 twist angle, per inch of length.

The extent of filament twist does not appear to be significantlyaffected by filament size, a 105-10 nylon yarn bulked under conditionsdescribed above having ap- 25 proximately 4 S and 8 Z twists, of atleast 5 twist angle, per inch of length. The larger filaments, however,were interentangled to a lesser degree, the yarn having a coherencyfactor of 2.

When further treated by the interlacing process disclosed in Bunting andNelson U.S. Patent No. 2,985,995, the bulky yarn bundle was renderedmore coherent by more intimate intenningling of the filaments withoutaffecting their crimp and twist. The coherency factor of the SS-denieryarn was increased to 15 by this treatment and the 105 yarn wasincreased to factors in the range 10 to 40. The interlacing treatment ofthe yarn imparted improved performance in textile operations andincreased abrasion resistance in woven fabric.

EXAMPLE XXII Continuous filament yarns of 66 nylon with filaments oftrilobal cross-section were melt-spun and drawn on heated rolls in anair chest at about 420 F. The filaments passed continuously from thedrawing zone at speeds in excess of 1000 y.p.m. to a fluid jet in whichthe filaments were subjected to the action of air at 420 F. and thendischarged upon a slowly moving screen surface. After separation fromthe air stream and cooling in a tensionless state on the moving surface,the filaments were conveyed to a windup. The yarn was overfed to the jetat a rate about 22% greater than the takeup speed.

The properties of yarns A, B, and C which were processed under the aboveconditions are shown in Table XIII. The trilobal cross-sectionalconfiguration of the filaments was unaflected by the fluid treatmentalthough the filaments were individually twisted with random alternate Sand Z twist portions.

In this example, the hot yarn from the drawing zone entered the crimpingjet at substantially the treating temperature. This facilitatedtreatment at high speed and was also found to increase the resistance ofthe dyed product to fading in the presence of fumes. It is frequentlydesirable, especially when producing the products of this invention athigh speed, for the feed yarn to be heated prior to introduction intothe heated fluid stream, although this is not a requirement to producethe described filamentary structures.

Table XIII Yarn A Yarn B Yarn 0 Feed Yarn:

Number of filaments 204 68 68 Amine ends (equiv./l0 g.) 40 13 Carboxylends (equiv./l0 g 65 98 36 Yarn twist 0 0 0 Acid dyeing rate (percent/l0mi 1. 08 0.83 1. 52 Bulked Yarn (as produced):

Denier 3, 700 1, 300 1, 300 Tenacity, g.p.d 3. 2 3.2 3. 0 Breakelongation, percent 47 45 40 Initial modulus, g.p.cl 5.8 7.0 G. 9Filament twist (number turn Z l I 6 5 5 Coherency factor. 45-75 BulkedYarn (alter boil-oil):

Crimp elongation (YCE), percent 68 100 Crimps per inch 14 15 18 Aciddyeing rate (percent/10 min.) 1. 92 1. 97 3.80 Increase in dyeing rate,pereent Yarn A comprised a bulky yarn with a coherent structure ofintimately interentangled filaments with random irregular curvilinearthree-dimensional crimp. The bulked yarn was particularly suited for themanufacture of carpets. The bulked yarn is unique in that the dyeingrate of the treated yarn is significantly greater than the untreatedyarn and yet the resistance of the dyed yarn (particularly when dispersedyes are used) to fading in the presence of sunlight or chemical fumes(N0 or 0 is substantially equivalent to the resistance of carpet yarnsof staple fibers which have been produced by more cost- 29 1ymechanically crimping heat-setting and yarn spinning processes.

Yarns B and C demonstrate the ability to produce yarns with the desireddegree of dyeability by appropriate choice of polymer composition. By ahigher proportion of amine ends in the fiber-forming polyamide, thereceptivity for acid dyes for the unbulked feed yarn and, in turn, thetreated product is greatly enhanced, with all other tensile, bulk andother physical properties being retained. The differences in dyereceptivity of yarns B and C, when Woven into tufted carpeting in apredetermined pattern and dyed competitively in the piece, produce adistinctive and desirable tone-on-tone effect.

In addition to the polyamide yarns illustrated in the examples, othersuitable yarn materials include the polyamides derived from meta xyleneaotdiamine and adipic acid; para xylene oux'diamine and azelaic acid;4,4- methylene biscyclohexlamine and azelaic, sebacic or dodecanedioicacid; or hexamethylene diarnine and sebacic acid. Poly(hexamethyleneisophthalarnide) may be employed as a homopolymer or as a copolymer withother polyamides. Vinyl polymers may be grafted to polyamides by meansof irradiation to improve dyeability, soil resistance, antistaticproperties or flame resistance.

Suitable polyester yarns, in addition to those already disclosed,include those of poly(hydroxypivalate), poly-(ethylene-2,6-nathphalate), poly-(tetrachloro diphenylol propaneisophthalate), poly(diphenylol propane isophthalate), poly(ethyleneterephthalate/bibenzoate), and poly(bicyclohexyldimethane bibenzoate).Polycarbonates may also be used.

The filaments may be modified with the conventional pigments,delustrants, fillers, antistatic agents, antioxidants, or otheradditives, and the polymers may be modified to adjust the atlinity forvarious dyestuffs. Polyamides, for example, may be modified by theincorporation during polymerization of a diamine salt of an alkyl oraryl phosphinic acid such as the hexarnethylene diamine salt of phenylphosphinic acid or by regulating the proportions of amine end groups.The acceptance of all dyestuffs by polyarnides is enhanced by theinclusion of other polymeric materials such as polyethylene oxide orpolyvinylpyrrolidone. The affinity of polyesters for basic dyes isincreased by modification with organic radicals, a preferred modifierbeing sodium sulfoisophthalic acid salt.

The bulky multifilament yarn of this invention has the desirableproperties of spun staple yarn and avoids the necessity of cuttingcontinuous filaments into staple and then reforming the staple intoyarn. The continuous filament bulky yarn is simply and economicallyprepared, by a process which requires little equipment, directly fromthe continuous filament bundle produced initially in synthetic fibermanufacture. The bulky yarn is superior to spun staple for many purposesbecause of its freedom from loose ends. The hand of fabrics made fromthe bulky yarn usually is stiffer than that of corresponding staplematerials, making them more suitable for use in draperies, suits,overcoats, etc. As discussed previously, staple yarns can be processedby this invention to improve bulk and achieve special effects.

The yarn is sufficiently uniform to be handled easily by textilemachinery and to form highly uniform fabrics without the sacrifice ofbulk or fiber interlocking charaeteristics that occur with somemechanically cri-mped yarns having too regular a structural pattern. Theyarn has been used without dilficulty on both automatic weaving,knitting, and tufting machines. The increased covering effectiveness offabric made with the bulky yarn permits the production of more fabricfrom the same weight of yarn and, in addition, by greatly extending theutility of artificial fibers, enables them to replace expensive orscarce fibers in many uses. An additional saving in yarn weight isrealized in tufted materials since the crimp is largely removed bytension provided in tufting so that much less yarn is used on thereverse of the base material. The relaxed yarn on the front side of thefabric, of course, will still have its high crimp and bulk.

The low denier yarns and monofils can be used in any normal textileoperations and end uses. They are particularly useful in the preparationof very light fabrics because of the greatly increased bulk and coveringpower per unit of weight. The heavy denier yarns have many uses normalto such yarns and are particularly suited as the pile element of pilestructures. They can be used as cut or loop pile in garments and rugs orcarpets. The high bulk permits the production of woven or tufted carpetswith much improved cover and resilience. The absence of loose fibersalso makes such structures very pill-resistant.

Another advantage is the suitability of this process for combiningfilaments of extremely fine denier into light bulky yarns, having ahighly uniform appearance, for which there is no spun staplecounterpart. More than one kind of filament may be processedsimultaneously to create yarns with a desirable blend of fibercharacteristics. Intermittent impul-sing of the multi-filament beingprocessed can be used to produce a novelty yarn having alternatingsmooth lengths and bulked regions produced according to the describedprocess. This can be accomplished by varying feed tension, feed rate, orfluid flow. A simple apparatus for achieving this efi'ect is disclosedby Frederick C. Field, in U.S. Patent No. 2,931,090.

Since many different embodiments of the invention may be made withoutdeparting from the spirit and scope thereof, it is to be understood thatthe invention is not limited by the specific illustrations except to theextent defined in the following claims.

We claim:

1. A monocomponent synthetic organic filament possessing alternate S andZ twist sections throughout its length; having a random number of turnsbetween twist reversals; having a random continuously varying angle oftwist along its length; having a random number of twist reversals perinch; and having at least one S turn and at least one Z turn per inchwhich have a twist angle averaging at least 5.

2. A filament of claim 1 prepared by shrinking a synthetic organicfilament at least 12% in length, said shrunk filament having amacromolecular structure such that its dyeability rate and tenacity aregoverned by the equation D) X To 0.8

where D and D are the dyeing rates of the filament before and aftershrinking, respectively, and T and T are the tenacities (grams perdenier) of the filament before and after shrinking, respectively.

3. A filament of claim 1 in which the twist angle averages at leastabout 10.

4-. A stable multi-filament strand comprising the filaments of claim 3.

5. A monocomponent synthetic organic filament possessing alternate S andZ twist sections throughout its length; having a random number of turnsbetween twist reversals; having a random continuously varying angle oftwist along its length; having a random number of twist reversals perinch; and having at least one S turn and at least one Z turn per inchwhich have a twist intensity (angle) equivalent to at least 20 turns perinch.

6. A monocomponent synthetic organic filament possessingalternate S andZ twist sections throughout its length; having a random number of turnsbetween twist reversals; having a random continuously varying angle oftwist along its length; having a random number of twist reversals perinch; having at least one S turn and at least one Z turn per inch whichhave a twist angle averaging at least 10; and having a random,persistent, threedimensional, non-helical, curvilinear, erimpedconfiguration continuously along its length and being substantially freefrom crunodal loops.

7. A synthetic organic filament having a uniform crosssectionalconfiguration (free from distortion) through out its length; having arandom, persistent, three-dimensional, non-helical, curvilinear, crimpedconfiguration continuously along its length; possessing alternate S andZ twist sections throughout its length; having a random number of turnsbetween twist reversals; having a random continuously varying angle oftwist along its length; having a random number of twist reversals perinch; and having at least one S turn and at least one Z turn per inchwhich have a twist angle averaging at least 8. A filament of claim 7composed of a erystallizable thermoplastic material.

9. A filament of claim 7 comprising a polyarnide.

10. A filament of claim 9 comprising poly(hexarnethylcne adipamide)having a long period of about 83 to 100 A., a tenacity of at least 3grams per denier and an orientation angle of about 17 to 40 and havingat least 10 crimps per inch.

11. A filament of claim 9 comprising poly(e silon caproamide) having along period of about 30 to 110 A., a tenacity of at least 2.5 grams perdenier and an orientation angle of about 17 to 35 and having at least 10crimps per inch.

12. A filament of claim 7 comprising a polyester.

13. A filament of claim 12 comprising a polyester of terephthalic acidand a glycol.

14. A filament of claim 12 comprising poly(hexahydro-p-xylyleneterephthalate).

15. A filament of claim 12 comprising poly(ethylene terephthalate)having a long period of at least 110 A., a tenacity (T of at least 1.0and an orientation angle of at least (474.0 T and having at least 5crimps per inch.

16. A filament of claim 12 comprising a copolymer of ethyleneterepht'nalate containing less than 15% combined monomers other thanethylene terephthalate and copolymerizable with ethylene terephthalateand having a long period of at least 110 A., a tenacity (T of at least1.0 and an orientation angle of at least (28-23 T and having at least 5crimps per inch.

17. A filament of claim 7 comprising linear polypropylene.

18. A filament of claim 7 comprising acrylonitrile polymer containing atleast 85% combined acrylonitrile.

19. A filament of claim 7 composed of cellulose acetate.

20. The filament of claim 7 in which the average filament crimpelongation after loading to 0.5 gram per denier and hot wet relaxationis at least 15%.

21. The filament of claim 7 in which the filaments have at least 10crimps per inch.

22. A filament of claim 7 in which the cross section of the filaments isnon-circular.

23. A stable bulky multi-filament strand comprising filaments of claim7, the crimp configuration of each filament being independent of thecrimp configuration of adjacent filaments.

24. A stable bulky multi-filament strand of claim 7 having a specificvolume at 3.1 lbs/sq. in. of between about 7 and about 14 cubiccentimeters per gram.

25. A multi-filament strand of claim 7 in which at least one filamentdiffers in composition from the remaining filaments.

26. A multi-filament strand of filaments having a circularcross-section; possessing alternate S and Z twist sections throughouttheir lengths; having a random number of turns between twist reversals;having a random continuously varying angle of twist along their lengths;having a random number of twist reversals per inch; and. having at leastone S turn and at least one Z turn per inch which have a twist angleaveraging at least 5; said filaments having lines of constantretardation which are parallel to the fiber axis throughout the lengthof the filament, said lines of retardation being visible in thebirefringence pattern produced by the filament under Nicols prismscrossed at wherever the axis of the filament lies at an angle of 45 toeach of the planes of polarization of the prisms and is perpendicular tothe axis of view.

27. A m-onocomponent synthetic organic filament possessing alternate Sand Z twist sections throughout its length; having a random number ofturns between twist reversals; having a random continuously varyingangle of twist along its length; having a random number of twistreversals per inch; and having at least one S turn and at least one Zturn per inch which have a twist angle averaging at least 5, having arandom, persistent, threedimensional, non-helical, curvilinear, crimpedconfiguration continuously throughout its length and being substantiallyfree from crunodal loops, said filament being prepared by shrinking asynthetic organic filament at least 12% in length, said shrunk filamenthaving a macromolecular structure such that its dyeability rate andtenacity are governed by the equation where D, and D are the dyeingrates of the filament before and after shrinking, respectively, and Tand T are the tenacities (grams per denier) of the filament before andafter shrinking, respectively.

References Cited by the Examiner UNITED STATES PATENTS 2,435,891 2/48Lodge 5734 2,439,815 4/48 Sisson 161-177 2,966,775 1/61 Seem et al.57-140 3,017,686 1/62 Breen et al 57140 MERVIN STEIN, Primary Examiner.

6. A MONOCOMPONENT SYNTHETIC ORGANIC FILAMENT POSSESSING ALTERNATE S ANDZ TWIST THROUGHOUT ITS LENGTH; HAVING A RANDOM NUMBER OF TURNS BETWEENTWIST REVISALS; HAVING A RANDOM CONTINUOUSLY VARYING ANGLE OF TWISTALONG ITS LENGTH; HAVING A RANDOM NUMBER OF TWIST REVERSALS PER INCH;HAVING AT LEAST ONE S TURN AND AT LEAST ONE Z TURN PER INCH WHICH HAVE ATWIST ANGLE AVERAGING AT LEAST 10*; AND HAVING A RANDOM, PERSISTENT,THREEDIMENSIONAL, NON-HELICAL, CURVILINEAR, CRIMPED CONFIGURATIONCONTINUOUSLY ALONG ITS LENGTH AND BEING SUBSTANTIALLY FREE FROM CRUNODALLOOPS.